The public does not need to stock up on A Influenza Antigen, and there is no need to test if there is no symptom

Reporter Zhang Jiaxing

On March 3, when the reporter searched on an e-commerce platform, he found that the search popularity of "influenza antigen" was as high as millions, and the price was much higher than that of the new crown antigen detection reagent, reaching more than ten times or even dozens of times.

"Flu A" is short for influenza A virus. With the recent increase in the proportion of infections, there is a strong demand for testing for influenza A virus. So, is the A Stream antigen test accurate? Why is it more expensive than the new crown antigen? Need to stock up in advance? With these problems, the reporter of Science and Technology Daily interviewed Gao Fu, an academician of the Chinese Academy of Sciences, on March 3.

Antiviral therapy can be given early after antigen testing

"The percentage of influenza-like cases in the northern and southern provinces remains high, with individual provinces declining." On March 3, the latest weekly surveillance report released by the National Influenza Center showed that the current circulating strain showed the characteristics of H16N1 subtype predominance of influenza A virus and co-circulating H1N3 subtype, and was sensitive to neuraminidase inhibitors and polymerase inhibitors.

"Susceptible" means that the virus has not developed resistance and that antiviral treatment is still effective.

"To fight viral infections, the timing of treatment is crucial." Gao Fu said that antiviral therapy within 48 hours of onset can effectively reduce influenza complications and reduce the chance of weight change.

It can be seen that within 48 hours of symptomatic symptoms, it can be effectively fought against the virus by identifying whether it is infected with influenza A and then blocking the replication and release of the virus in the body.

So, the same fever, cough, fatigue, how to tell if infected with influenza A virus?

"In practice, it can be found that the amount of detoxification is generally higher within 1 week after the onset of symptoms, and the detection rate is higher at this time. Specifically, if infected with influenza A virus, it can be detected the day after symptoms appear or when you have a fever. Therefore, antigen testing can help to carry out antiviral treatment early, Gao Fu said.

"Rapid antigen detection methods can use colloidal gold and immunofluorescence, and these initial diagnoses can facilitate the rapid implementation of antiviral therapy." Gao Fu said, but its sensitivity is lower than that of nucleic acid test, so the interpretation of rapid antigen test results should be combined with the patient's epidemiological history and clinical symptoms.

Do A Flu Antigen Kits cost more?

"In contrast, among the two methods of antigen detection, the immunofluorescence method requires the antibody coating of the target protein (NP protein), which is more expensive to manufacture than the colloidal gold method kit." Gao Fu responded to the Science and Technology Daily reporter that for the new crown antigen and A stream antigen detection, the process and cost of the two methods are similar.

In general, colloidal gold methods are used for testing "quick test strips", while enzyme-linked immunofluorescence kits are mostly used by laboratory professionals. Most of the influenza antigen test kits that can be purchased on e-commerce platforms are colloidal gold method.

The reporter searched the e-commerce platform and saw that the amount used for A stream detection was about 30 yuan, and the amount used for new crown testing was about 3-5 yuan. Gao Fu explained: "The process and cost of the two are similar, and the current price difference may be due to the relatively small market for A flow kits, the small production volume of manufacturers, and the relatively high cost sharing, or it may be that there are few similar products on the market and the price is not fully competitive." Therefore, open market competition and wide promotion and use can promote product upgrading and reduce prices. ”

The reporter used "influenza" as the keyword to search for the listed detection reagents belonging to the medical device category on the official website of the State Food and Drug Administration, and found that Beijing Wantai, Guangzhou Wanfu, Hangzhou Aybo and other enterprises have A stream antigen detection kits approved for marketing.

In the column of "structure and composition/main components", it can be seen that a complete detection kit is basically composed of "tube, liquid, card", "tube" is used for dissolution, "liquid" is buffer, retain antigen activity, and the test card carries "synthetic antibody" to explore virus-specific proteins. From the perspective of the structure and composition of the kit, its composition is not much different from the new coronavirus antigen detection kit.

"A flu antigen test kits can be used after symptoms appear, in conjunction with the probability of possible contact with the source of infection. Testing is not required if there are no symptoms. Therefore, the general public does not need to stock up. Gao Fu pointed out that the original intention of "stockpiling" may be to be one step ahead of the virus, but in the final analysis, the function of the kit is only to find the virus, not to "stop" the virus. In order to fortify the virus in advance, the most practical and effective way is to vaccinate against influenza to enhance influenza A virus resistance.